1. Field of the Invention
The present invention relates to an USB application device, more specifically, to a compact USB application device.
2. The Related Art
Because Universal serial bus (USB) interface has advantages of high convenience, high compatibility and high transmission speed, it is widely applied to various electronic devices such as personal computers, MP3 players, MP4 players, external storage devices, laptops, flash storage devices, etc. Hence, USB interface becomes one of the standard interfaces of the electronic devices.
A conventional USB compatible application apparatus is disclosed in U.S. Pat. No. 7,165,998. The USB compatible application apparatus has a printed circuit board (PCB) to be a carrying board inside of a connector. A top surface of the PCB carrying board includes a plurality of terminals. A board bottom sandwich is formed between a bottom surface of the PCB carrying board inside the connector and a covering shell of the connector. At least one electrical element is fixed on the bottom surface of the PCB carrying board inside the connector.
Therefore, the present invention can shorten the length of the USB compatible application devices or improve working efficiency of the USB compatible application device. The thickness of the connector is further reduced because the thickness of the PCB carrying board is approximately 0.3 millimeter (mm) to 1 mm.
Furthermore, the board bottom sandwich has at least one supporting structure, front end protection layer, and a combination thereof capable of connecting to the PCB carrying board. Hence, the supporting structure can fix the size of the board bottom sandwich and prevent the board bottom sandwich from transforming by the unexpected outer force. The front end protection layer can protect the electrical element located inside the board bottom sandwich and meanwhile efficiently strengthen the structure of the board bottom sandwich.
However, the front end protection layer and the supporting structure merely support a front side and lateral sides of the PCB carrying board inside the connector. There is not any supporting structure in central area of the board bottom sandwich for supporting a central portion of the PCB carrying board inside the connector.
If a corresponding USB connecting bracket plugs into a connecting sandwich formed between the top surface and the covering shell inside the connector, then the terminals of the corresponding USB connecting bracket will press the PCB carrying board into the connector. Hence, the central portion of the PCB carrying board inside the connector may be damaged because the PCB carrying board is thin and approximately 0.3 mm to 1 mm and there is not any supporting structure supports the central portion of the PCB carrying board inside the connector to resist the pressing force from the USB connecting bracket.